Rotary volumetric machine

ABSTRACT

Rotary volumetric machines of the type having spaced pairs of oppositely disposed sector-shaped pistons can be adapted as pumps, compressors, and engines. This machine is driven by a simplified and direct driving means due to the unique piston supporting means. One pair of pistons is held by a quill shaft and the other pair by a hollow shaft or sleeve surrounding the shaft, the construction being such that the shaft and sleeve can be directly driven. The driving motion is transmitted to the solid shaft and to the hollow shaft by offcenter devices.

United States Patent [72] Inventor Chauncey R. Drury 1308 Stonewall. Loubvllle. Ky. 40222 883.178

Dec. 8. 1969 July 13. 1971 {21 1 Appl. No. [22) Filed [451 Patented [54] ROTARY VOLUMETRIC MACHINE 14 Claims. 7 Drawing Pip.

[521 U.S.Cl. 418/36 [50] Field 01 Search 418/36. 35. 37

[56] Relereuees Cited UNITED STATES PATENTS 1.401.478 12/1921 KelIerJr. 418/36 X 2.124.327 7/1938 Wolstenholme 41813625..

2.631.545 3/1953 lonesmm. 4l8/36X 2.678.155 5/1954 Durham 418/37 3.203.405 8/1965 Sabet 418/36 X 3.396.632 3/1968 Leb1anc.. 418/36 3.483.578 12/1969 Harrison 418/37 Primary Examiner-Carlton Rv Croyle Assistant Examiner-Wilbur .1. Goodlin Attorney-Norman L. Wilson. Jr.

ABSTRACT: Rotary volumetric machines of the type having spaced pairs 01' oppositely disposed sector-shaped pistons can be adapted as pumps. compressors. and engines. This machine is driven by a simplified and direct driving means due to the unique piston supporting means. One pair 01' pistons is held by a quill shaft and the other pair by a hollow shaft or sleeve surrounding the shatt. the construction being such that the shaft and sleeve can be directly driven. The driving motion is transmitted to the solid shaft and to the hollow shaft by oftcentcr deviees.

PATENTEUJULIBIQH $592,57

SHEET 1 BF 2 FIG-I INVENTOR.

CLHAUNCEY R B ATTORNEY PATENIEU JUL 1 3 IBYI SHEET 2 OF 2 ROTARY VOLUMETRIC MACHINE BACKGROUND OF THE INVENTION This invention relates to a rotary volumetric machine of the type having a first pair of oppositely disposed sector-shaped pistons within a cylindrical chamber in alternating arrangement with a second pair of oppositely disposed pistons angularly spaced from the first pair. Rather than moving back and forth along the axis of the cylinder, the pistons herein rotate about this axis. As pointed out in US Pat. No. 3,396,632 such rotary volumetric machines operate at excellent efficiencies as liquid or gas pumps, vacuum pumps, compressors, hydraulic fluid driven engines, internal combustion engines, and mutual combinations of such engines.

In rotary engines the two sets of sector-shaped pistons, through various gearing arrangements, are rotated within the cylinder at relatively periodically variable speeds. For example in both U.S. Pat. Nos. 3,203,405 and 3,396,632 planet gears, indirectly linked to the pistons, rotate on the internal toothing of a rim gear. A second less desirable piston control means described in U.S. Pat. No. 3,203,405 involves uniformly driving one piston by rotating an operating shaft while nonuniformly driving the other piston through a crank arm and a planet gear.

It has been found that while they are mechanically sound, rotary engines of the prior art are quite complex. Consequently, these engines have not been highly successful commercially. Thus in U.'S. Pat. No. 3,203,405 the control is accomplished by a rotating disc which has a boxlike cross section having a side or radial wall whichis supported on the hollow shaft by a support ball bearing. Recesses are provided in the circumferential cylindrical wall of the rotating disc in order to make it possible to retain the diameter of the rotating disc comparatively small, and to permit movement of elliptical gears. In U.S. Pat. No. 3,396,632 a disc rotates in a coaxial sense within a gearcase. At least one auxiliary shaft is pivoted within the case which carries, on one side, a pinion or planet wheel engaging a rim integral with the gearcase. On the other side two components which are offcenter are carried in such a manner that the piston groups rotate at varying speeds. By the practice of this invention the pistons are rotated by a simplified and direct driving means. Due to the manner of assembling the pistons it is possible by the apparatus herein to employ piston driving means using fewer moving parts. Such driving means results in a less complex, more efficient engine.

SUMMARY OF THE INVENTION According to the practice of this invention a rotary volumetric machine of the type having two pairs of sector-shaped pistons rotatably disposed in a hollow cylinder is simplified by the combination of unique piston-supporting means with power means operating effectively and efficiently therewith. In the piston-supporting means one pair of pistons is held for part of its length against a rotatable sleeve adapted to surround a central quill shaft. The other piston pair is held for part of its length against a fixed sleeve or enlarged quill shaft end portion. The rotatable sleeve encircles the shaft and, in the assembled machine, the end thereof seats against the fixed or stationary sleeve. When the'rotatable sleeve is thus seated, the pistons face each other. The power means include a stationary gear mounted perpendicular to the center shaft at a point outside the cylinder with its center in alignment with the shaft center. At least one planet gear is mounted to engage, mesh with and revolve around the'stationary gear. Through a first oifcenter device the circular motion of the planet gear is communicated through the hollow shaft to one pair of pistons, and similarly through a second offcenter device the motion is also communicated through the center shaft to the other pair of pistons.

DETAILED DESCRIPTION OF THE INVENTION An advantage of the apparatus of this invention is that with minor design modifications an almost limitless number of compression ratios is possible. Another advantage of the invention is that the piston-driving means can be spaced away from the cylinder when desirable. The apparatus permits a large displacement in a relatively small unit and the rotation of the pistons is not unidirectional. The apparatus can be constructed with pistons operating in the reverse direction. As an engine the apparatus of this invention operates without valvetiming devices since the arrangement of parts permits the spaces (volumes) between the piston walls and confined by the cylinder wall to communicate freely with openings about the circumference of the cylinder wall, thereby providing for the introduction of a fuel mixture, a means of ignition, and an opening for the discharge or exhaust of gases. Thus, this invention is useful as a four-stroke engine operating either as a gas compression engine, or as a diesel engine, without valves.

In one of the more important aspects of this invention a volumetric machine can be made in which wear, due to moving parts, is compensated for by the mode of construction. In my preferred embodiment a pair of plates are rigidly attached to sleeves at their ends, one plate being secured to the stationary sleeve at its end away from the seat mentioned hereinbefore, the other plate being secured to the rotatable sleeve at its end away from the seat. These plates are generally circular and sized to match the inside of the hollow cylinder. If a cylinder jacket is employed which closes on these plates, wear is compensated for as indicated. The plates move toward each other as the pistons and the bearing surface or seat resulting from the abutment of the stationary and rotatable sleeves wear as a result of friction.

A more complete understanding of the construction, operation and advantages of the apparatus of the invention will be obtained by reference to the accompanying drawings illustrating several embodiments of the invention,.and to an explanation of the various views in the drawings.

In the drawings FIG. I is a perspective diagram of one form of the apparatus of the invention. 1

FIG. 2, also in perspective, shows the pistons of the invention.

FIG. 3 is a longitudinal sectional view of the piston driving means or power takeoff as the case may be.

FIGS. 4a through 4d show in diagrammatic presentation the operating cycles of various embodiments of the machine.

Before considering the entire machine contemplated herein, the fabrication of the pistons should be understood since the efficiency and simplicity of the apparatus is largely due to the mode of piston construction. Referring therefore first to FIG. 2, two pairs of pistons 2a, 2b and 4a, 4b are shown. These pistons are generally sector-shaped vanes with their apexes directed toward the center of the cylinder, and one pair is the same length as'the other so that they can be adapted for rotation with the front side of one piston facing the backside of the other piston. As can be seen in FIG. 2 pistons 2a and 2b are attached to a stationary sleeve or enlarged shaft end 6 whereas pistons 4a and 4b are attached to rotatable sleeve 8. Stationary sleeve 6 is welded or otherwise made integral with the far end of operating shaft 10. Sleeve 8 is made slideable on operating shaft 10, the inside diameter of sleeve 8 being approximately equal to the outside diameter of the operating shaft. In order to be disposed opposite each other the pistons are supported on the sleeves by only half their lengths and consequently extend beyond the sleeves. When sleeve 8 is slid onto operating rod 10 until it abuts sleeve 6, the pistons face each other as shown in FIG. 1. The pistons on sleeve 8 extend beyond sleeve 8 opposite sleeve 6. Since the pistons are exactly twice the length of their respective central sleeves, their end surfaces abut plates 12 and 14. In addition sleeves 6 and 8 seat against each other forming a fluidtight enclosure when confined within a cylinder sleeve.

By this arrangement, a hollow shaft 8 communicates with the first pair of pistons, and a solid shaft, or quill shaft 10 within, communicates with the second pair of pistons. Of course the pistons on one sleeve could extend a greater distance and the pistons on the other sleeve a lesser distance beyond their sleeves. Pistons 2a and b and 4a and b can be placed in the cylinder chamber without further modification. However in my preferred embodiment ends or plates 12 and 14 are used to compensate for wear as previously noted. The pistons are held against the sleeves and plates. They can be attached to the plates and abut the sleeve or attached to the sleeves and abut the plates. Desirably they will be integral with both.

An entire cylinder of my preferred type is shown in FIG. 1. it is noted that sleeve 6 seats against sleeve 8. In addition piston 40 is slideable against piston end 12 whereas piston 2b abuts piston end 14. The piston welds 16 can be seen in FIG. 1. However any means of attaching the pistons to the sleeves can be used. The entire cylinder is encased in a cylinder jacket 18 which is held by anchor 20 to prevent its rotation during operation. Stanchion 22, having a base to which anchor 20 is secured, is provided with upright 24. Upright 24 is provided with a bearing 25 to support rod 10.

An advantage of the apparatus of this invention is that, due to the construction of the pistons as described in conjunction with FIG. 2, the rotation of the pistons to achieve compression and expansion stages is more effectively accomplished than heretofore. This will be readily understood by reference to FIGS. 1 and 3. The operational advantages are attributed in part to the fact that shaft 10 and sleeve 8 can be directly driven. When the sleeve and shaft are nonuniformly rotated, the pistons will be rotated in the same manner.

The rotation of shaft 10 and of sleeve 8 relative to each other in a nonuniform manner such that the pistons approach each other and then spread apart is accomplished in one embodiment of the invention by a stationary gear 36 and two planet gears 32 and 34. In this preferred embodiment planet pinions 32 and 34 are geared to fixed gear 36, and are positioned on opposite sides of fixed gear 36 so that they revolve around the fixed gear while also rotating on their own axes. Fixed gear 36 is mounted on a nonrotatable shaft 40 supported by frame 42 and surrounded by housing 44.

In the embodiment of FIG. I in order to translate the motion of the planet gears to shaft 10 and to sleeve 8, offcenter devices are employed. Referring first to planet gear 34, a crankshaft 50, journaled into the center of planet gear 34, carries a crank pin 52. One end 54 of a crank arm is pivotally connected to this crank pin. The other end 57 of this crank arm, through pivotal connection 56, is immovably attached to shaft 10, being held in place by key 58 and bolt 60. Through fixed key connection 62 sleeve 8 is similarly operated by planet gear 32 through crankshaft 64, crank pin 66 and crank arm 68 having a pivotal connection 70 and movable end 7 I. Crarikshafts 50 and 64 do not rotate within the planet gears but are secured therein to turn as planet gears 32 and 34 rotate. This brings about the rotation of shaft 10 and of sleeve 8 to be described in connection with FIG. 4.

Referring first again to FIGS. 1 and 3, a cylindrical enclosure 80 can be seen. Ends 81 and 83 of crankshafts 50 and 64 are seated in bearings in this enclosure. In addition the ends of crankpins 52 and 60 opposite crankpins 50 f'and 64 are equipped with additional crankshafts 82 and 84 respectively which are rotatably carried by the side of the enclosure opposite ends 81 and 83. These ends are mounted in bearings 86 and 88. It can be seen that as crankshafts 50, 82 and 64, 84 rotate, the enclosure 80 will also rotate. Enclosure 80 is, therefore, a flywheel. An output or input shaft 90, depending on whether the unit is a pump or a motor, is rigidly attached to the outside of the flywheel.

As has been pointed out as planet gears 32 and 34 revolve on the outside of stationary gear 36, they also rotate about their axes. As a consequence shafts S0 and 64 will also rotate and crank arms 54 and 68 will operate to bring about the movement of crank arms. With two pairs of pistons the mechanical or gear ratio of planet gear 32 or 34 to fixed gear 36 is exactly 2:1. This ratio determines the number of times per revolution that pistons 2a and 2b and 4a and 4b (i.e., two and four) move with each revolution of flywheel in FIG. 3. If three pairs of pistons are used, the ratio will be 3:1 etc. Movement of the pistons must be constant and synchronized with the openings or ports 92 in cylinder wall 94. Stationary gear 36 does not revolve. Its function is to maintain the coordination specified hereinbefore. It is also the fulcrum point for the transmission of motion between the crank arms and the flywheel.

The operation of the rotary volumetric machine as well as other embodiments of the invention can be seen in FIGS. 4:: through 4d. The length of these arms plus the effective crank center of gears 32 and 34 (i.e. the distance from the center of the planet gear to the pivot point, which is the length of crankshaft 50) must be selected for travel of pistons 2 and 4. The length of connecting rods 53 and 55 must also be selected so that movement of 2 ahead of, or behind 4, or the distance between these members at the end of stroke is equal, regardless of length of travel.

The acceleration of crank arms 51 and 52 is alternatingly nonuniform. This acceleration is due to the offcenter attachment rods 53 and 55, and to the fact that as planet gears 32 and 34 revolve around gear 36, they also rotate on their individual axes. Referring to FIGS. 4a and 4b the consistency of this alternating pattern is due also to the fact that the end of crank arm 51 is trailing behind the center point of gear 32 whereas the end of crank arm 52 is leading ahead of the center point of gear 34. With this connection the positions of arms 51 and 52 are shown at the end of each 90 travel of planet gears around the stationary gear. When gears 34 and 32 revolve from the 3 and 9 o'clock positions on the stationary gear respectively (FIG. 4a), to the 12 and 6 positions (FIG. 4b), the angle between arms 52 and S1 closes. When the gears rotate from the i2 and 6 oclock positions to the 9 and 3 o'clock positions, the angle widens. In one revolution of the planet gears the angle between arms 51 and 52 opens and closes twice. Since this force is transmitted directly to the pistons by virtue of the construction of the machine, the piston angles also open and close twice per piston revolution. Intake and exhaust ports 92 and spark plugs (not shown) will be placed accordingly as described in U.S. Pat. No. 3,203,405.

As indicated hereinbefore the apparatus herein will perform as a pump, compressor, or engine. Other modifications will occur to those skilled in the art. Thus whereas two planet gears are employed in my preferred embodiment, it will be apparent from FIG. 40 that the same translation of motion will be achieved by the use of one planet gear. If offcenter attachment rods 53 and 55 are attached as shown in FIG. 40, the second planet gear can be eliminated. However it will be desirable to employ a second planet gear 35 as a balance. in order to use one planet gear one of the crank arms such as 51 is extended in the opposite direction forming a second crank arm 51. When attachment rod 55 is connected from a point on planet gear 34 common with rod 53 to crank arm 51', the pistons will operate as in FIGS. 40 and 4b. The length of crank arm 51' will of course be equal to that of crank arm 52. For balance purposes crank arm 52 will be extended to form crank arm 52.

Another embodiment, and one which will be more rugged than the others, will be constructed according to the diagram shown in FIG. 4d. Both 51 and 52' are formed 180 opposite crank arms 51 and 52 and all four crank arms are connected to the two planet gears 32 and 34 as shown. Attachment rods 53 and 55 are connected to planet pinion 32. These rods operate crank arms 51 and 52'. Crank arms 51 and 52 are operated by planet pinion 34 through attachment rods 53 and 55'. The volumetric machine is thus strengthened by four crank arms.

In another modification since pistons will always be in the same place within the cylinder for each compression and expansion stage, an actual opening in the cylinder at the center of the piston arc will not be detrimental to engine operation.

This means that an expansion joint 98 can be provided parallel to the piston edge the length of the cylinder. The edge of this joint is shown in FIG. 1. Other variations contemplated are those leading to the fixing of the smallest angle between pistons (i.e. the compression ratio). Obviously this angle will be smaller in the case of a gas than if the apparatus contains a liquid. The angle between the pistons will be determined by the length of the crank arms and the length or throw of the crankshafts. If either (but not both) is lengthened, the angle is changed. In addition, taking the distance of the crank arms from the center of operating shaft 10, the length of crank arm 57 plus the length of crankshaft 50 must be equal to the length of crank arm 68 plus the length of crankshaft 64. Desirably all crankshafts must be of equal length and all crank arms must be of equal length. In addition it is understood that the height of the cylinder of the machine need not necessarily exceed the diameter of the base. The engine can be either elongated or flat. Among other variations in the apparatus are changes in mounting means, in the construction of the flywheel, and in additions to the cylinder adapting it as a pump, compressor, or engine, with shaft 90 being either to supply or take off power. These and other ramifications are deemed to be within the scope of this invention.

What I claim is:

1. In a rotary volumetric machine of the type having two pairs of pistons in the form of sector-shaped vanes rotatably disposed in a hollow cylinder within a housing each pair of pistons being diametrically arranged within the cylinder, extending the full length of the cylinder, with the first pair of pistons being capable of angular rotation relative to the second pair such that the machine is suitable as a compressor, engine, or pump, piston-supporting means comprising a center shaft adapted to be positioned along the axis of the hollow cylinder, means supporting one end for rotation within the cylinder, means supporting the other end at an opening through which it extends outside the cylinder, a pair of sleeves each adapted to surround the center shaft, one being a stationary sleeve, the other being a rotatable sleeve, the stationary sleeve immovably surrounding the center shaft at the shaft end supported within the cylinder, the rotatable sleeve surrounding the center shaft at the shaft end which extends through the cylinder, said rotatable sleeve slideably encircling the shaft end for rotation thereabout with one of its ends seated against the stationary sleeve, a pair of plates rigidly attached to the sleeves, one plate being secured to the stationary sleeve at its end away from the seat, the other plate being secured to the rotatable sleeve at its end away from the seat, the first pair of pistons being rigidly held against the stationary sleeve and its plate but extending beyond said sleeve the length of the cylinder opposite the rotatable sleeve, the second pair of pistons being rigidly held against the rotatable sleeve and its plate but extending beyond the sleeve so that the pistons face each other.

2. In a rotary volumetric machine of the type having two pairs of pistons in the form of sector-shaped vanes rotatably disposed in a hollow cylinder within a housing each pair of pistons being diametrically arranged within the cylinder, extending the full length of the cylinder, with the first pair of pistons being capable of angular rotation relative to the second pair such that the machine is suitable as a pump, compressor, or engine, the combination of l) piston-supporting means comprising a center shaft positioned along the axis of the hollow cylinder, means supporting one end for rotation within the cylinder, means supporting the other end for rotation at an opening through which it extends outside the cylinder, a pair of sleeves adapted to surround the center shaft, one being a stationary sleeve, the other being slideably rotatable on the center shaft, the stationary sleeve immovably surrounding the center shaft at the shaft end supported for rotation within the cylinder, the rotatable sleeve surrounding the center shaft within the cylinder at the shaft end extending through the cylinder, said rotatable sleeve encircling the shaft end for rotation thereabout with one of its ends seated against the stationary sleeve, the first pair of pistons rigidly attached against the stationary sleeve but extending beyond said sleeve the length of the cylinder opposite the rotatable sleeve, the second pair of pistons being rigidly secured against the rotatable sleeve but extending beyond the sleeve so that the pistons face each other; with (2) power means comprising a circular stationary gear mounted perpendicular to the center shaft at a point thereon outside the cylinder, with the center of this gear lying on a line through the center of the shaft, a planet gear meshing with the stationary gear and mounted to engage and rotate around the outside of the stationary gear, a first offcenter device connecting the planet gear to the center shaft in such a manner that the center shaft becomes a crankshaft, a second identical offcenter device connecting the planet gear to the rotatable sleeve encircling the center shaft in such a manner that the sleeve also becomes a crankshaft.

3. The rotary volumetric machine of claim 2 wherein a pair of plates are rigidly attached to the sleeves, one plate being secured to the stationary sleeve at its end away from the seat, the other plate being secured to the rotatable sleeve at its end away from the seat and wherein the sizes of gears are such that each planet gear to stationary gear mechanical ratio is 2:1.

4. The rotary volumetric machine of claim 3 wherein the pistons are attached to plates but abut the sleeves.

5. The rotary volumetric machine of claim 3 wherein the pistons are attached to the sleeves but abut the plates.

6. The rotary volumetric machine of claim 3 wherein the pistons are integral with both the sleeves and the plates.

7. The rotary volumetric machine of claim 6 wherein the offcenter devices are crank arms pivotally connected to a crankshaft immovably fixed to the center of the planet gear and wherein a second planet gear is disposed from said planet gear and is also adapted to rotate around the stationary gear.

8. The rotary volumetric machine of claim 7 wherein the first crank arm is connected through a crankpin to a crankshaft on one planet gear and the second crank arm is connected through a crank pin to a crankshaft on the second planet gear, the length of the first crank arm and crankshaft being equal to the length of the second crank arm and crankshaft.

9. The rotary volumetric machine of claim 8 wherein the planet gears are carried by crank arms which extend through bearings at the centers of the gears and which are rotatably connected to a flywheel.

10. The rotary volumetric machine of claim 7 wherein a jacket surrounds the pistons and plates forming ends of the hollow cylinder containing the sector-shaped pistons, in a friction fit to form the remainder of the housing.

11. The rotary volumetric machine of claim 10 wherein the jacket contains a slit the length of the jacket at a line opposite and parallel to the sector are which enables the cylinder circumference to be made smaller to maintain a seal between the pistons and the inner cylinder wall after use.

12. The rotary volumetric machine of claim 7 wherein the stationary gear, the planet gears and the crank arms are mounted in a cylinder which becomes the flywheel.

13. The rotary volumetric machine of claim 12 wherein an output or input shaft is mounted in the center on the outside of the cylinder.

14. The rotary volumetric machine of claim 12 wherein the cylindrical flywheel is enclosed in a stationary housing. 

1. In a rotary volumetric machine of the type having two pairs of pistons in the form of sector-shaped vanes rotatably disposed in a hollow cylinder within a housing each Pair of pistons being diametrically arranged within the cylinder, extending the full length of the cylinder, with the first pair of pistons being capable of angular rotation relative to the second pair such that the machine is suitable as a compressor, engine, or pump, pistonsupporting means comprising a center shaft adapted to be positioned along the axis of the hollow cylinder, means supporting one end for rotation within the cylinder, means supporting the other end at an opening through which it extends outside the cylinder, a pair of sleeves each adapted to surround the center shaft, one being a stationary sleeve, the other being a rotatable sleeve, the stationary sleeve immovably surrounding the center shaft at the shaft end supported within the cylinder, the rotatable sleeve surrounding the center shaft at the shaft end which extends through the cylinder, said rotatable sleeve slideably encircling the shaft end for rotation thereabout with one of its ends seated against the stationary sleeve, a pair of plates rigidly attached to the sleeves, one plate being secured to the stationary sleeve at its end away from the seat, the other plate being secured to the rotatable sleeve at its end away from the seat, the first pair of pistons being rigidly held against the stationary sleeve and its plate but extending beyond said sleeve the length of the cylinder opposite the rotatable sleeve, the second pair of pistons being rigidly held against the rotatable sleeve and its plate but extending beyond the sleeve so that the pistons face each other.
 2. In a rotary volumetric machine of the type having two pairs of pistons in the form of sector-shaped vanes rotatably disposed in a hollow cylinder within a housing each pair of pistons being diametrically arranged within the cylinder, extending the full length of the cylinder, with the first pair of pistons being capable of angular rotation relative to the second pair such that the machine is suitable as a pump, compressor, or engine, the combination of (1) piston-supporting means comprising a center shaft positioned along the axis of the hollow cylinder, means supporting one end for rotation within the cylinder, means supporting the other end for rotation at an opening through which it extends outside the cylinder, a pair of sleeves adapted to surround the center shaft, one being a stationary sleeve, the other being slideably rotatable on the center shaft, the stationary sleeve immovably surrounding the center shaft at the shaft end supported for rotation within the cylinder, the rotatable sleeve surrounding the center shaft within the cylinder at the shaft end extending through the cylinder, said rotatable sleeve encircling the shaft end for rotation thereabout with one of its ends seated against the stationary sleeve, the first pair of pistons rigidly attached against the stationary sleeve but extending beyond said sleeve the length of the cylinder opposite the rotatable sleeve, the second pair of pistons being rigidly secured against the rotatable sleeve but extending beyond the sleeve so that the pistons face each other; with (2) power means comprising a circular stationary gear mounted perpendicular to the center shaft at a point thereon outside the cylinder, with the center of this gear lying on a line through the center of the shaft, a planet gear meshing with the stationary gear and mounted to engage and rotate around the outside of the stationary gear, a first offcenter device connecting the planet gear to the center shaft in such a manner that the center shaft becomes a crankshaft, a second identical offcenter device connecting the planet gear to the rotatable sleeve encircling the center shaft in such a manner that the sleeve also becomes a crankshaft.
 3. The rotary volumetric machine of claim 2 wherein a pair of plates are rigidly attached to the sleeves, one plate being secured to the stationary sleeve at its end away from the seat, the other plate being secured to the rotatable sleeve at its end away from the Seat and wherein the sizes of gears are such that each planet gear to stationary gear mechanical ratio is 2:1.
 4. The rotary volumetric machine of claim 3 wherein the pistons are attached to plates but abut the sleeves.
 5. The rotary volumetric machine of claim 3 wherein the pistons are attached to the sleeves but abut the plates.
 6. The rotary volumetric machine of claim 3 wherein the pistons are integral with both the sleeves and the plates.
 7. The rotary volumetric machine of claim 6 wherein the offcenter devices are crank arms pivotally connected to a crankshaft immovably fixed to the center of the planet gear and wherein a second planet gear is disposed 180* from said planet gear and is also adapted to rotate around the stationary gear.
 8. The rotary volumetric machine of claim 7 wherein the first crank arm is connected through a crankpin to a crankshaft on one planet gear and the second crank arm is connected through a crank pin to a crankshaft on the second planet gear, the length of the first crank arm and crankshaft being equal to the length of the second crank arm and crankshaft.
 9. The rotary volumetric machine of claim 8 wherein the planet gears are carried by crank arms which extend through bearings at the centers of the gears and which are rotatably connected to a flywheel.
 10. The rotary volumetric machine of claim 7 wherein a jacket surrounds the pistons and plates forming ends of the hollow cylinder containing the sector-shaped pistons, in a friction fit to form the remainder of the housing.
 11. The rotary volumetric machine of claim 10 wherein the jacket contains a slit the length of the jacket at a line opposite and parallel to the sector arc which enables the cylinder circumference to be made smaller to maintain a seal between the pistons and the inner cylinder wall after use.
 12. The rotary volumetric machine of claim 7 wherein the stationary gear, the planet gears and the crank arms are mounted in a cylinder which becomes the flywheel.
 13. The rotary volumetric machine of claim 12 wherein an output or input shaft is mounted in the center on the outside of the cylinder.
 14. The rotary volumetric machine of claim 12 wherein the cylindrical flywheel is enclosed in a stationary housing. 